By the very nature of the utilization of liquid substances including noxious chemicals, liquid hydrocarbon fuels, sulfide liquors, and any other objectionable or hazardous chemical material, it is frequently necessary to transfer a liquid fuel from a first storage vessel in which it is contained to a second storage vessel. Some instances include inter-plant transfers of liquids and gases in chemical plants, loading and off-loading tanker trucks and rail tankers, the re-fueling of aircraft, etc. Another instance in which it is necessary to so transfer a liquid fuel is in the case of re-fueling an automobile, including race cars during a racing event.
One particular class of automobile racing requires competing vehicles to travel an extended period of time to cover the pre-determined distance of the race. Such automobile races are popular and current NASCAR and other events include such races as the Indianapolis 500, the California 500, the Virginia 500, and the New England 300. Such automobile races typically require drivers and their cars to travel hundreds of miles from start to finish.
Since the fuel-carrying capacity of a race car is limited by the rules of racing and the capacity of such tanks is not sufficient to enable the racer to complete an entire race on a single tank load of fuel, it is a general requirement that drivers must take pit stops periodically for re-fueling. The amount of time used by a racing team for combined maintenance operations including re-fueling is usually a significant factor in determining the outcome of a given race. Hence, it is highly desirable from the standpoint of a racing team that time expended in re-fueling and other pit-stop operations is kept to an absolute minimum.
Current state-of-the-art for re-fueling a racing vehicle in a circle-track application is for the racer to pull their car into a “pit-stop” for servicing. As is customary, the on-board fuel tank of a racing vehicle includes an inlet conduit through which fuel is admitted to the on-board fuel tank during re-fueling. The prior art also uses a cap or other means of sealing the inlet conduit from the surrounding environment after a re-fueling of the vehicle is complete.
During a re-fueling, members of the pit crew tote a large funnel-shaped recharging tank or “dump can” which contains a desired amount of a motor fuel, about 11.5 US gallons in the case of some racing events. The recharging tank includes a fitting on its lower extremity which is complementary to that on the end of the inlet conduit on the vehicle's fuel tank. Once the vehicle comes to a stop, the pit crew removes the cap from the fuel tank inlet. Then, the fitting on the recharging tank is mated to the fitting on the tank inlet to form a sealed conduit through which fuel may pass from the recharging tank to the vehicle's on-board fuel tank, thus providing a fluid transfer coupling. A valve disposed on the recharging tank is opened, and fuel contained within the recharging tank is drawn by gravity into the on-board fuel tank of the vehicle. A headspace volume exists above the liquid level of the fuel in the tank, and initially when the tank is full, the headspace volume is at its minimum. As fuel is consumed, the headspace volume increases, and reaches its maximum when all of the liquid fuel formerly contained in the tank has been consumed.
The re-fueling of a racing vehicle is undertaken as expediently as possible while minimizing fuel loss during the operation. However, one disadvantage of prior art methods and fluid transfer couplings is that significant volumes of liquid fuel are spilled onto the pavement and portions of the vehicle being re-fueled upon de-coupling of the fluid transfer coupling's mating halves from one another. A volume of fuel lost by spillage in re-fueling operations during the course of a race can be several gallons, such losses occurring primarily when the recharging tank is removed from the inlet conduit on the receiving vessel. While pit crews are well-equipped to deal with inadvertent fires that may occasionally occur, there are immediate health risks to pit crew personnel other than the fire hazard. For example, modern racing engines are typically designed to require fuels having high octane ratings. Volatile anti-knock compounds such as tetraethyl lead and the like are sometimes formulated into racing fuels as octane boosters. These lead compounds are volatile and since they are known health hazards, the issues of inhalation and transdermal absorption of tetraethyl lead and related compounds may possibly pose a serious threat to health. In addition, any un-necessary release of raw hydrocarbon fuels into the atmosphere is of concern for environmental reasons.
Another issue concerning storage tanks is the concept of vapor lock. Vapor lock is a condition manifest by the pressure in the headspace above the fuel in a storage tank being lower than normal atmospheric pressure. In the case of automobiles, such a condition is caused to exist by virtue of the fuel pump removing fuel from the fuel tank, without the same volume of air being admitted into the tank to compensate for the lost volume of fuel owing to the fuel tank being sealed off from the atmosphere. Eventually, the fuel pump is required to pump fuel from an area of reduced pressure, and, not being designed for such use, a less-than-desired amount of fuel is delivered to the engine, which can result in decreased engine performance.